Publish samples to the store

[kmelmon]

Make each sample able to pass store verification.
a. Make each sample pretty. Currently the UI looks somewhat random and unnatural
b. Publish to the store.

[michalleptuch]

I made small sample for WPF but I still get error when I upload package to the Store:
Package acceptance validation error: You cannot submit pre-compiled .NET Native packages. Please upload the Microsoft Store appxupload file and try again.

https://github.com/michalleptuch/rounded-flyout